NEW YORK (Dow Jones) -- Merrill Lynch, the nation's largest broker, reported a loss Wednesday for the third quarter and said the its write downs for bad loans and related securities was almost $8 billion, well above the firm's own previous estimate from just a few weeks ago. The very faceless nature of online mortgages makes them difficult to trust. There is, after all, much sensitive information that you would have to give out when you apply for a mortgage. Such information may include your social security number, your full name, your address, your monthly income, et cetera. Thus, it is therefore advisable that you only conduct these types of online transactions with an established institution.